Gilles Deleuze (1925–1995) is widely recognized to have been one of the most influential and important French philosophers of the second half of the twentieth-century. During his lifetime, Deleuze authored more than twenty-five books, all but one of which have now been translated into English. His work has typically been divided into three periods:

• 1950s-1960s: Deleuze began his career by writing traditional monographs on various classic figures in the history of philosophy, including Hume (1953), Nietzsche (1962), Kant (1963), Bergson (1966), and Spinoza (1968). After this philosophical apprenticeship in the history of philosophy, Deleuze published his magnum opus, Difference and Repetition (1968) a work in metaphysics and ontology, followed by a treatise on logic entitled Logic of Sense (1969).

• 1970s: His second period was marked by his collaboration with Félix Guattari, with whom he wrote a two-volume work of political philosophy entitled Capitalism and Schizophrenia (1972; 1980), the first volume of which was written in the wake of the events of May 1968, and is often read as a philosophical reaction to it. Chaosmosemedia is an important site dedicated to Guattari’s work.

• 1980s-1990s: Deleuze’s last works initially focused on questions of aesthetics, and included books on painting (Francis Bacon: The Logic of Sensation, 1981), the cinema (The Movement-Image, 1983; The Time Image, 1985), the Baroque (Leibniz and the Baroque, 1988), and literature (Essays Critical and Clinical, 1993), as well as his book Foucault (1986), which he published after the untimely death of Michel Foucault in 1984. He ended his career with a culminating reflection on the nature of philosophy entitled, simply, What is Philosophy? (1991).

Many of these works have since become classics in their respective fields. Nietzsche and Philosophy (1962) has long been recognized as one of the landmark interpretations of Nietzsche, and Difference and Repetition (1968) is one of the seminal works of twentieth-century European metaphysics.

Given the diverse directions of his thought, Deleuze has had a wide-ranging impact, not only on philosophy, but also on numerous fields in the humanities, including not art history, film studies, and literary theory, among others. He remains one of the most cited authors in the humanities, and the secondary literature on his writings is already immense and growing rapidly. Even during his lifetime, Deleuze’s significance was recognized by his peers. “I consider him to be the greatest living French philosopher,” Michel Foucault declared in 1978, even going so far as to predict, in an oft-cited remark, that “perhaps, one day, this century will be called ‘the Deleuzian century.’”

Within the French philosophical field, Deleuze nonetheless occupies a somewhat singular position, since the terms most frequently used to describe the various strains of European thought (phenomenology, hermeneutics, structuralism, postmodernism, etc.) are largely inapplicable to his work.  Unlike his compatriot Jacques Derrida, Deleuze never engaged in the “deconstruction” of texts or word play. Indeed, Deleuze conceived of philosophy as the creation of concepts, and his writings take the form of precise deductions of concepts. For this reason, Deleuze’s work often transcended the divide, in the discipline of philosophy, between the so-called “continental” (European) and “analytic” (Anglo-American) traditions. His monographs in the history of philosophy, in particular, are recognized in analytic philosophy for the clarity and rigor (and originality) of their analyses. In France, many of them have become required reading for the agrégation exam in philosophy, which allows one to teach within the French university system—a sign that his writings have achieved a certain canonical status within the discipline.